1. Field of the Invention
The present invention relates to a motor which is provided with a stator core which has a noncircular outside shape, an apparatus for production of a motor, and a method for production of a motor.
2. Description of the Related Art
Known in the art is a motor which is provided with a stator core which is comprised of a plurality of stacked core sheets which are comprised of rolled magnetic steel sheets wherein the magnetic steel sheets are stacked with rolling directions made different from each other to thereby reduce cogging torque which is generated due to magnetic anisotropy of the magnetic steel sheets (for example, Japanese Patent Publication No. 2005-65479A).
The above core sheets are generally fabricated by press-working and thereby punching a hoop which is conveyed along its rolling direction. If the magnetic steel sheet which is described in the above patent publication has a regular polygonal outside shape, the maximum dimensions in the direction perpendicular to the rolling direction will differ between core sheets which are stacked so that the rolling directions differ from each other.
For this reason, if considering the case of punching out these core sheets from a common hoop, since the maximum dimension of the hoop in the direction perpendicular to the conveying direction differs, excess parts end up occurring in the hoop corresponding to the fluctuations in the maximum dimensions. Due to this, the amount of the hoop which is discarded ends up increasing. This has led to an increase in the manufacturing costs.